The present invention relates to glucose monitoring systems and methods, and more particularly to a system that monitors the amount and rate of change of glucose in a patient, providing an easy-to-read display of such monitored information, as well as an alarm if either the amount or rate of change exceeds programmable limits.
Glucose is a simple sugar containing six carbon atoms (a hexose). Glucose is an important source of energy in the body and the sole source of energy for the brain. Glucose is stored in the body in the form of glycogen. In a healthy person, the concentration of glucose in the blood is maintained at around 5 mmol/l by a variety of hormones, principally insulin and glucagon. If the blood-glucose concentration falls below this level neurological and other symptoms may result, such as hypoglycemia. Conversely, if the blood-glucose level is raised above its normal level, e.g., to above about 10 mmol/l, the condition of hyperglycemia develops, which is one of the symptoms of diabetes mellitus. It is thus evident that maintaining the concentration of glucose in the blood at a proper level is critically important for wellness and good health.
Unfortunately, some individuals, either through disease, dramatic and/or sudden changes to the body (such as may be caused by injury or surgery), or for other reasons, are unable to maintain the proper level of glucose in their blood. In such instances, the amount of glucose can usually be altered, as required, in order to bring the glucose concentration to a proper level. A shot of insulin, for example, can be administered in order to decrease the glucose concentration (insulin decreases the amount of glucose in the blood). Conversely, glucose may be added directly to the blood through injection, an intravenous (IV) solution, or indirectly by eating or drinking certain foods or liquids.
Before the glucose concentration can be properly adjusted, however, an attending physician (or the patient himself or herself), must know what the present glucose concentration is and whether such concentration is increasing or decreasing. Unfortunately, the only viable technique heretofore available for measuring glucose concentration has been by drawing a blood sample and directly measuring the amount of glucose therein, or by measuring the amount of sugar in the urine. Both measurement techniques are not only inconvenient for the patient, but also may require significant time, manpower, and the use of expensive laboratory instruments, tools or aids to complete. As a result, it is usually not possible for a physician to know immediately what the glucose concentration of a given patient is. Rather, fluid samples must first be obtained, tested or analyzed, and a report issued. Based on such report, appropriate corrective action can then be taken when needed, e.g., through insulin injections or IV supplements, to move the glucose concentration back to an acceptable level. Unfortunately, however, because of the inherent time delay involved with gathering the fluid samples, performing the analysis, and issuing the report, such corrective action may not be possible until several hours after it is first needed. Even after the report is issued, the report results may be misinterpreted, or (e.g., through transcription or analysis error) may simply be wrong. Hence, it is apparent that what is needed is a way to accurately determine the glucose concentration of a patient immediately, effectively communicate such measured concentration to a physician or other interested person (including the patient) with minimum likelihood of error, and provide a clear indication of whether such concentration is within certain prescribed safe limits.
Even after the glucose concentration is known, the physician must still estimate how much corrective action is required until such time as a direction and rate of change of the glucose concentration level has been established. Unfortunately, to identify a trend in the glucose concentration using existing techniques, i.e., to determine whether the glucose concentration is increasing or decreasing, and at what rate, a series of the above-described body fluid measurements must first be made, and the results then analyzed. Such measuring and analyzing process only further delays any appropriate corrective action. What is clearly needed, therefore, is a glucose measurement system that provides a physician, or other medical personnel (or the patient himself or herself) with a rapid measure or indication of the rate of change of the glucose concentration, thereby immediately informing the physician whether any corrective action is needed.
The present invention advantageously addresses the above and other needs.